The era from 1840 to 1893 was a momentous one both for German-American immigration and for U.S. industrialization, so it bears examining to what extent the two developments were interrelated. This essay will first sketch out the contours of German immigration and American industrialization in this era. It then identifies areas of the U.S. economy where Germans were particularly concentrated, and examines the industrial and geographic niches where transatlantic connections were of greatest consequence. Shifting focus from global to individual patterns, it then explores what was German and what was American about German-American entrepreneurship in the mid- and late nineteenth century.